| Abstract |
This paper presents a new modulation concept for three-to-single-phase direct AC/AC modular multilevel converter-based railway interties. The concept minimizes the inherent harmonic coupling between the two grid sides and is therefore particularly suited to operation at very low cell numbers and switching frequencies. Moreover, it facilitates the use of specific modulation methods, such as optimized pulse patterns. Additional aspects, such as the influence of cell capacitor voltage ripple as well as circulating current control, are also considered. The latter can be integrated into the control concept in a straightforward manner. |
